The efficacy of brief interventions for substance abuse is well-established. Further, numerous opportunities exist for brief access to high proportions of individuals with substance use disorders; an ideal example is the post-partum period, during which nearly all parenting women are hospitalized. However, three factors limit the potential of brief interventions. First, the ability to conduct such interventions is dependent upon willingness to disclose drug use. This is a significant obstacle given evidence that as few as half of drug positive individuals-particularly women in the perinatal period-report that use. Second, there are logistic and financial obstacles to implementing even brief intervention programs, particularly with regard to training and provider willingness. Third, over half of eligible patients do not complete brief interventions that require attendance at more than a single opportunistic session. The current study will thus develop and pilot test methods for addressing (a) the need to identify drug users regardless of willingness to disclose; and (b) the need for a feasible, replicable, and low-cost single-session intervention that does not require disclosure of drug use. Specifically, this exploratory/developmental (R21) study will develop and validate the Wayne Indirect Drug Use Screener, or WIDUS, which will be designed to predict drug use risk without relying on self-disclosure. A comprehensive checklist of indirect factors associated with drug use disorders will be developed, and tested against hair and urinalysis in a sample of 300 post-partum women. The 10-30 items most predictive of hair and urinalysis will be cross-validated in an additional sample of 100 post-partum women. In addition, existing software designed to build motivation to change among post-partum drug users will be modified so as to build motivation without presuming drug use. This logistically feasible, replicable, and low-cost brief intervention will be subjected to Phase I preliminary testing in preparation for a future Phase II clinical trial. If validated, the WIDUS and its associated computer-based indirect intervention could provide a cost-effective, replicable, and inoffensive method for intervening with persons who do not wish to disclose illicit drug use. In this way, the risks of illicit drug use to both mother and child could be reduced, even with the large group of women who would not otherwise have been identified or intervened with because of hesitancy to disclose. [unreadable] [unreadable] [unreadable]